This application claims priority upon German Patent Application 199 49 954 3, filed on Oct. 16, 1999.
The present invention relates to a method for analyzing and optimizing a multistage manufacturing process, in which, in order to achieve predefined product properties, tuning steps are carried out, their type, number and extent being variable.
Methods of the type mentioned at the beginning occur in various sectors of industrial production. Examples which may be mentioned are the chemical industry, the foodstuffs industry, steel manufacture, the manufacture of pharmaceuticals, mechanical engineering or automobile construction. In these sectors, xe2x80x9cbatch-modexe2x80x9d processes occur again and again, in which, in order to produce a product, a xe2x80x9cstandard parts listxe2x80x9d of constant manufacturing steps is worked through and, following this, a variable sequence of tuning steps is further carried out in order to set one or more product properties to a predefined value or a value desired by the customer.
A multistage manufacturing process of the type mentioned is present in particular in the manufacturing of chemical products from mixtures of substances. Examples of this are foodstuffs, ointments or coatings. In this case, because of fluctuating properties of the starting products or specific requirements on the final product, after the standard recipe has been worked through, there is often a product from the manufacturing process which is still inadequate in terms of the desired product property. For this reason, small quantities of different additives are subsequently added in individual steps. In the case of coatings, these are, for example, toning pastes, water, rheological aids and other additives. It is not unusual for twenty or more additives per batch to have to be used for the manufacture of a coating, in order to obtain products in accordance with a specification. In addition to the desired properties of a chemical product, in particular of a coating, the pH value, the density, the color locus or the viscosity can be included in addition to the color.
In the manufacture of other products, correspondingly different properties may be the objective of the tuning. For example, in the manufacture of electronic circuits, these may be specific electrical properties, it being possible for the tuning steps in the manufacture of the circuit to consist in altering electrical parameters.
The tuning steps necessary to achieve predefined product properties make the manufacturing process more expensive and more complicated, so that in principle it would be desirable to mange with the smallest possible number of these.
The object of the present invention is therefore to provide a method which permits the analysis and optimization of multistage manufacturing processes of the type mentioned in the background.